Hi everyone,

anybody knows where I could get KGSS boards ?

Thanks

Lilknight is where many of us got the board from. PM him to see if he has got any left.

Would that be KGSSHV boards?

A little late to the party shubert. Ya could get lucky...

Edited November 19, 201213 yr by livewire

A question for those of you who eard about the KGSSHV : I have a SR 507 running on a old SRM T1. I expect the KGSS to be more detailed, with better controled bassed without lossing the magic on the vocals provided by the T1.

Do you think that would be the case or do I have to go for the BH described by KG on Headwize ?

julien

I have had several quotes and am just about to order KGSSHV board sets onboard heatsink. 2.5oz copper, blue mask, lead solder tinned. If I order 20 sets they will be app £45/set inc VAT within EU.

Shipping to you will be a few pounds on top of that. I would like to place order in a week to 10 days, delivery will be app 3 weeks after.

PM me if you'd like to be included.

A question for those of you who eard about the KGSSHV : I have a SR 507 running on a old SRM T1. I expect the KGSS to be more detailed, with better controled bassed without lossing the magic on the vocals provided by the T1.

Do you think that would be the case or do I have to go for the BH described by KG on Headwize ?

julien

Either KGSS, KGSSHV or BH will be a big step up from the T1. Personally I do not feel the difference between a regular KGSS and regular BH were that big, but YMMV and all that, my biggest differences come from changing transducers and some sources vs similar amps.

I'll try KGSSHV with a standard pot, and then with silver TVC from Audio consulting http://www.audio-consulting.ch/?Parts:Silver_Rock_TVC. Just to speak about my system, I used to have a Weiss Firewire Minerva with Macbook, Trinnov ST1, Audio consulting SWGLA and MIPA DIY preamp and amp running on heavy solar batteries, finally DIY Janus of audionec type http://www.audionec.com/.

As I moved on a smaller house, I came on head-fi. I kept my minerva, testing a new dac (Metrum Octave which is very very nice http://www.nosminidac.nl/Octave_English.html with audio GD interface), the T1 and SR507.

I would just like to mention how audioprana cables http://audioprana.free.fr/catalogue%20vente%20en%20ligne.htm are good (from power, digital and interconnect) : far better than all I could test and quite cheap to build.

But my dream Stax amp would be : http://www.audio-consulting.ch/?Products:Amplifier:MIPA_Stax_Amplifier maybe next DIY step..........

But let's stay on earth for the moment with the KGSS !!!!

you got to be kidding me about all those pricings, especially for the transformer pot. Apparently the silver one costs $1600 each and you need 2 for stereo and 4 for balanced. On top of that, each is 9cm*9cm*9cm. Where the hell are you going to fit four of those.

As for your dream Stax amp... it costs *$20,000* Holy crap, what is it made out of ?! You can hire some one to build you a T2s with that kind of money. Also, what's up with all those battery powered snake oil that they are selling. 120Watt Battery Powered Mono Block... ehhh.... how big is your battery? (and no a generator is not a battery)

seriously, just stick to KGSS(HV), put a RK50 in there and be done with it.

I know that sound crazy, but it is working on LiFePO4 batteries.

By the way, what important part of KGSS can be of good quality for sonic improvments ?

Resistors on signal path ? Condo on the PS ?

Condos are nice. Try something equatorial.

I know that sound crazy, but it is working on LiFePO4 batteries.

(...)

I'm pretty sure i'm done with the power supply, schematics and board layout updated.

Tests indicate about 12 microvolts of noise at full power. Its when the diodes turn on, and

using the 35ns soft recovery diodes, even ceramic caps across them make no difference.

Over the range 10C to 50C and under full load the power supply voltage changes only 1.2 volts.

Measuring this is not at all easy. So i'll call it a better than -140db power supply and be done with.

http://gilmore.chem....gsshvpower3.pdf

spacers added to the non-insulated parts, update in a few minutes.

http://gilmore.chem..../kgsshvps7c.jpg

also dual cap sizes for spritzer, and heatsinks for luvdunhill

Even if you piled up a large stack of car batteries, the resulting noise would be more than

10 microvolts.

What is the advantage of LiFePO4 batteries?

Does the PS need any alteration when adopting SiC diodes?

Condo on the PS ?

??

Edited November 20, 201213 yr by justin

The PSU already uses very good diodes so no need to worry about that. Better resistors might give some improvement but the real upgrade would be more current, much more current to the output stage. The circuit is very linear so it kept it's characteristics as the current was lowered to work with those onboard sinks but it doesn't mean it wasn't a compromise. Huge sinks, large PSU and this amp can mean business.

If I understand well, better choose outboard sink and large power transformer would bring more current ?

Hope my question is not too stupid, as I am not considering myself as an expert

Well that and adjusting the amp boards for the output stage to draw more current.

Recently, been getting more and more irritating static noise from my volume pot. It's definitely coming from the dact. Infact, from day one the static noise was already there but, only in one channel and I put up with it. Recently, its been getting worse and its now in both the channels. Anyone has the same problem?

Edited November 27, 201213 yr by Victor Chew

Singapore’s humidity wouldn’t be doing it many favours . Have you tried cleaning the contacts?

http://www.dact.com/html/contact_cleaning.html

Thanks alot John. I will have to go get the turner 600. Yes, Singapore is a humid place. I do keep the equipment covered after use but little dust does not mean no dust.

You can clean the DACT by taking it apart but it will never be truly noise free. Those plastic housings are just about useless...

Right channel went sparky last Friday..... I believe something fell on the right 100ohm resistor right after the B- input and fried abunch of parts with it. There is a part of the resistor that got blown away... I now have two pieces of paper covering the vent holes right above the amp boards. (not taking any chances now...it's not good for the heart)

This is basically how I'm going to ground everything.. The pot and amp boards are grounded directly on the PSU board now. The switch circuit is grounded via the ground on the case, which is grounded to the PSU. The XLR ground is directly to the jack itself.

Hopefully this is the end to all ordeals...

Where did you ground the PSU? I can't see it. Why didn't you just use a star ground?

I like how you used terminal blocks for the pot. You used the same XLRs with built in terminal block I used. I like them.

Edited November 29, 201213 yr by eggil

Congratulations jwzhan!

Everyone wants happiness. No one wants pain. But you can't have a raimbow without a little rain..

Thank you for all the kind words, but I was too optimistic about everything.... I left the amp on for balance and bia adjustments. About 2 hours in, I heard a light pop... and again... the same problem.. something is burning my 100 ohm resistors..

the green Xs are the ones that got burned..

These are the exact same ones that got burned last Friday, but what's different is that last time they were burned instantanrously right after I turned the amp on, while this time they were burned during operation.. (Before all these, the amp didn't experience any problem even if I left it on for 22 hours straight.)

Any idea what's causing this?

This is truely testing my mental and physical strength... these ordeals are really bad for the heart...

@eggil

I modified a terminal block, soldered that onto the PSU and ran the ground from IEC to that directly.

There is a star ground; it's on the PSU. I'm only using the case as a conductor and shielding ground.

I copied the terminal on XLR thing from your built. I like it a lot as well.

It's on the HV line so that would be the most obvious point of failure. As to why it's happening it can be any number of things.